mysql，mysql mysql_real_connect 內存泄露

轉自：http://blog.csdn.net/weihua1984/archive/2010/08/24/5835731.aspx

linux 下使用c操作mysql數據庫時寫個測試程序

int?main(void)??
{??
????MYSQL?m_mysql;??
????mysql_init(&m_mysql);??
??????
????const?char?pLocalhost[]?=?"localhost";??
????const?char?pUser[]?=?"root";??
????const?char?pPass[]?=?"123456";??
????const?char?pDB[]?=?"HTTPCONTROL";??
??????
????if(mysql_real_connect(&m_mysql,pLocalhost,pUser,pPass,pDB,0,NULL,0)?==?NULL)??
????????cout<<"connect?failed"<<endl;??
????else??
????????cout<<"connect?success"<<endl;??
???????
????mysql_close(&m_mysql);??????
????return?0;??
}??

編譯后使用valgrind檢測內存泄露

[root@localhost string]# valgrind --tool=memcheck --leak-check=full ./mysql?
==10352== Memcheck, a memory error detector
==10352== Copyright (C) 2002-2009, and GNU GPL'd, by Julian Seward et al.
==10352== Using Valgrind-3.5.0 and LibVEX; rerun with -h for copyright info
==10352== Command: ./mysql
==10352==?
connect success
==10352==?
==10352== HEAP SUMMARY:
==10352==???? in use at exit: 61,336 bytes in 16 blocks
==10352==?? total heap usage: 118 allocs, 102 frees, 115,929 bytes allocated
==10352==?
==10352== 24,528 bytes in 6 blocks are possibly lost in loss record 4 of 5
==10352==??? at 0x4005903: malloc (vg_replace_malloc.c:195)
==10352==??? by 0x30DD75: my_once_alloc (in /usr/lib/mysql/libmysqlclient.so.15.0.0)
==10352==??? by 0x30E59C: ??? (in /usr/lib/mysql/libmysqlclient.so.15.0.0)
==10352==??? by 0x30EF96: ??? (in /usr/lib/mysql/libmysqlclient.so.15.0.0)
==10352==??? by 0x30F111: get_charset_by_csname (in /usr/lib/mysql/libmysqlclient.so.15.0.0)
==10352==??? by 0x32C3D2: mysql_init_character_set (in /usr/lib/mysql/libmysqlclient.so.15.0.0)
==10352==??? by 0x32DABB: mysql_real_connect (in /usr/lib/mysql/libmysqlclient.so.15.0.0)
==10352==??? by 0x8048A76: main (str.cpp:32)
==10352==?
==10352== 28,616 bytes in 7 blocks are possibly lost in loss record 5 of 5
==10352==??? at 0x4005903: malloc (vg_replace_malloc.c:195)
==10352==??? by 0x30DD75: my_once_alloc (in /usr/lib/mysql/libmysqlclient.so.15.0.0)
==10352==??? by 0x30E57A: ??? (in /usr/lib/mysql/libmysqlclient.so.15.0.0)
==10352==??? by 0x30EF96: ??? (in /usr/lib/mysql/libmysqlclient.so.15.0.0)
==10352==??? by 0x30F111: get_charset_by_csname (in /usr/lib/mysql/libmysqlclient.so.15.0.0)
==10352==??? by 0x32C3D2: mysql_init_character_set (in /usr/lib/mysql/libmysqlclient.so.15.0.0)
==10352==??? by 0x32DABB: mysql_real_connect (in /usr/lib/mysql/libmysqlclient.so.15.0.0)
==10352==??? by 0x8048A76: main (str.cpp:32)
==10352==?
==10352== LEAK SUMMARY:
==10352==??? definitely lost: 0 bytes in 0 blocks
==10352==??? indirectly lost: 0 bytes in 0 blocks
==10352==????? possibly lost: 53,144 bytes in 13 blocks
==10352==??? still reachable: 8,192 bytes in 3 blocks
==10352==???????? suppressed: 0 bytes in 0 blocks
==10352== Reachable blocks (those to which a pointer was found) are not shown.
==10352== To see them, rerun with: --leak-check=full --show-reachable=yes
==10352==?
==10352== For counts of detected and suppressed errors, rerun with: -v
==10352== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 3

mysql、還是網上找最后找到了

http://dev.mysql.com/doc/refman/5.0/en/mysql-library-end.html

簡單的說是在斷開數據庫連接后使用

mysql_library_end()

關閉MYSQL 使用的庫

MySQL server，即在mysql_close(。。。)

后添加

mysql_library_end();

就ok了

再添加一句，在使用mysql API之前最好是

Java 內存泄漏。調用mysql_library_init(。。。。)